Link http://google-maps-utility-library-v3.googlecode.com/svn/trunk/markerclustererplus/images/m1.png

is broken. Trying to access this image gives

Appliance Error (internal_error)

An unrecoverable error was encountered: ""

This problem is unexpected. Please use the contact information below to obtain assistance.

All other m-images (m2-m5) are OK.